1. Field of the Invention
In general, the present invention relates to an image processing apparatus, an image processing method and a medium for storing an image-processing control program. In particular, the present invention relates to an image processing apparatus and an image processing method for correcting the balance of color as well as relates to a medium for storing an image-processing control program for the image processing apparatus and the image processing method.
2. Description of the Prior Art
Traditionally, correction of the balance of color in many cases means correction of the so-called color fog or the like. That is, correction of the balance of color implies processing to correct a color slippage observed in equipment such as an image inputting apparatus.
In a digital still camera, for example, image data is output as a gradation-color-specification data of the RGB (red, green and blue) colors. In this case, data with the so-called color slippage due to characteristics of a lens or a CCD device employed in the digital still camera is also observed. An example of the color slippage is a state in which a particular color such as the red color is emphasized more than the color of the real object of observation.
When it is desired to make some compensations of image data for a color slippage thereof by using the conventional image processing apparatus, the data is read by an image processing program and an operator weakens the component value of an emphasized color by carrying out a predetermined operation on a trial-and-error basis.
However, the conventional method for correcting a color slippage has the following problems.
In the first place, carried out by an operator manually on a trial-and-error basis, the correction has a lack of accuracy. For an untrained operator, the correction is difficult to do.
In the second place, since only predetermined component values are increased or decreased in a uniform manner, in some cases, the correction can not be said to be done for all gradations.
Furthermore, if the data contains abnormalities other than just the color slippage, the correction can not be said to be effective.
In addition, it is basically impossible to form a judgment as to whether gradation-color-specification data for each component representing the color of every picture element is correct or not without comparing the color with a standard one. Considering the fact that there are possibly some cases in which it is a matter of course that a component is emphasized by rather an external factor, we can not help saying that it is extremely difficult to automatically form a judgment as to whether or not a color slippage exists.